Drive time to the trailhead depends only a little on the route taken. Going there, I left SR87 at about 0658 and arrived the trailhead parking lot around 0821, for a distance of around 19 miles and a elapsed time of about 83 minutes. Slow road in parts, but completely 2WD street car quality. Had to compete with mountain bikers on the way up.

On the return to civilization, I left the parking lot at 1251, went down the 10 miles of the dirt road to SR188, then up to regain SR87 and then to the SR87 – Four Peak road / Cline Cabin road. That was a total of 62 miles (11 dirt) and 51 miles at highway speed. The elapsed time for that return path was about 1245 to 1412, or 87 minutes. On this side, had to compete with buggy drivers coming up. Actually longer in distance and time but subjectively, the east side dirt road was less stressful than the west. But enough to justify the extra distance? Meh.

Arrived at upper parking area. Sierra Estrella high point is about center in the distance at around 62 miles.

Looking up at Brown’s Peak from the parking area. This parking lot appears to be an overflow for the main lot immediately at the trailhead. However, I like this one a bit better as the view is much wider.

To the southeast with Roosevelt Lake below.

Up the trail a short bit, and able to look back to the truck parked in the upper lot.

Trail is well defined until getting up to the rock.

Looking north toward Mt Ord (the radio communications site) and Mazatzal Peak, the next major bump to the left and the one I summited two weeks before.

More thorny shrubberies.

Up a little higher, looking down into the Tonto Basin.

The Superstitions and The Flatiron in the left middle ground.

Looking up toward Browns Peak.

Spring has sprung – buds on the trees.

The bottom of the chute. This is quite steep. Fortunately, it’s not on a ridge line so there’s little or no wind, and the only way to fall is down %^)

Looking at the crowd atop Browns from the rise atop the chute.

Toward the Salt River canyon with the Browns slope to the left and Brother/Sister/Amethyst to the right.

Atop Browns looking back toward the lower summit.

Didn’t find a benchmark, but this is interesting. Also, did find the peak register and signed in there.

The other 3 of the Four Peaks, with The Flatiron hidden behind Brother peak.

Looking at Mazatzal about center in the image, and realizing it’s 250′ higher.

Headed down the chute, with folks coming up. There are the two in the foreground and one about 100′ below. It’s hard to perceive the extreme slope in this photo.

Looking back up the chute with some people either climbing up or down (hard to see in the glare).

While not a cakewalk, it was surprisingly straightforward. Definitely was sometimes at the edge of scary in the chute, mostly coming down. Some large rocks are only metastable. Several times while descending I realized that the drop below me was too great, so I had to retreat a bit and find a more doable way down.

Drove up to Pinal this morning to swap out some equipment. Getting to/from Pinal from the highway isn’t difficult, just 18 miles, with 12 of them on a really great-condition (at least until the rains come) dirt road.

Once I was finished with my other hobby, I started down the road and parked at the Signal Peak turnoff (651B). As I’d never been to Signal, and I’d never used the mobile PeakBagger app to record a hike, I was able to do both and learn a thing or two or three new things.

The first thing I learned was that Signal was less than 300′ minimum prominence, and that’s what I’d set my PeakBagger filter for, so Signal didn’t show up until I dialed that down to 250′.

For the White Tank peaks, I’m lazy. I can get the key and drive. This morning I went up to check on the radio site on the east ridge where I have an ADS-B receiver and a railroad data receiver setup. The Windows PC there had apparently died a while back, the ADS-B link failed at the beginning of April, so it was time to fix things.

The cool thing about the White Tank road is it goes through the old Caterpillar proving grounds, where they pitted Caterpillar bulldozers against the mountain. And the White Tank road was part of the testing arena.

Verrado’s north end currently ends at the golf course; the tower road is the wide diagonal that heads northwest into the narrows up-canyon.

While Verrado continues to inch its way up the lower portions of the road, it’s unlikely it’ll ever get up this far. This what I call “the bowl”, where Caterpillar dozers not only moved millions of tons of rock back and forth for test and fun, but also cut the 20%-grade, ~0.6 mile long ramp that climbs north out of the bowl and then descends into the White Tank park boundaries.

On this fine day, there’s plenty of people walking the ramp. It’s windy as heck out, and the temperatures are in the mid-50’s, but the sun is warm.

Hauled out the dead PC. Am rebuilding it now to put back on the hill in the next week or two.

No radio sites, just a nice, challenging, quiet hike on a somewhat cool and breezy day.

Looking up at Woolsey from the northside trailhead.

There are sheer cliffs and difficult escarpments everywhere.

The way up is to pick the right river of lava boulders and other detritus.

However, it’s not easy a priori to know the best route. Boulders can be loose, and i stepped on one, it rolled, and I crash-landed.

Lava-rock-boulder rivers near or at angle of repose. While a 2′ size boulder appears to weigh a lot, putting one’s weight into it for purchase can cause it to shift or break loose.

This is the true Gila Peak (Woolsey Peak) benchmark.

From the top of the mountain looking due north. The vertical beige strip is the final section of the dirt road with the trailhead at the bottom (south) end. The rivers of lava rock are punctuated with bunch grass.

Another view north.

From the false peak.

Looking to the west from the benchmark.

Somebody disposed of a lead-acid car battery here a long time ago. What it was powering up here on the summit is a mystery.

From that battery, bits of lead plate everywhere.

Another view to the north. The trailhead is at the close end of the road below. The nice thing is one can see the trailhead and their vehicle pretty much all the time during the hike. Of course, if something bad happens down at the trailhead, there’s not much one can do from this vantage other than watch, unless one has a very powerful rifle %^)

View to the east from the benchmark; White Tank to the left and the Sierra Estrella to the right.

Looking to the SE over many lava-flow ridges. Table Top is on the horizon to the left of center.

The White Tank mountains are way off in the distance.

The back side of the Sierra Estrella range; the characteristic shape of Sierra Estrella high point is quite distinctive.

One of the BM locations, desert varnish and graffiti.

One of the peak registers.

Time to return to the truck. It always seems to me to be harder the do the return than the ascent; here, it was mostly boulder-hopping down the slope, keeping aim on distant horizon features to maintain the right azimuth, and paying attention to the next step to avoid boulders likely to move or the possibility of critters, none of which were seen on this trip.

While one vehicle had arrived at the trailhead, turned around, and then left during my hike, there were no other signs of folks having been here during my time.

The drive back out to old US 80 was uneventful. Stopped by 8-Bit Ale Works on the way back for a pint.

From the parking lot, Woolsey’s in-between the two saguaros. There was one other vehicle in the lot.

Trail register.

Timber at the top of the ascent trail. This is the SE end of the mesa.

A solar powered radio facility! And all camo’ed out.

While I do not know its purpose or owning agency, it definitely appears to be some sort of relay site, with the cheesy, wire omni antenna (even with an antenna BNC connector, who’d have thunk?), perhaps monitoring VHF high-band transmitters around the peak and relaying messages/signals from them on some UHF frequency using the directional Yagi antenna in the green radome.

Amazing that the panels are not damaged or missing.

The equipment enclosure. Must have batteries and the two radios inside.

The antenna connector at the bottom of the case. Note the green ground wire, so someone working on this has some fleeting idea of the correct insulation color for ground. However, it’s interesting that no critter has chewed through the insulation.

Honestly, I’d be so embarrassed to hoist an antenna as crappy looking as the VHF high-band omni on the right. And what’s worse, the connector used there is a BNC, definitely not rated for outdoor environments.

From the trail-top timber post, looking at the high point of Table Top. There is a very deep gulley/draw between there and here and the trail to the peak is around the east side of the mesa.

As I get closer to the true peak, a shot back toward the SE end of Table Top – the radio equipment and trail-top timber are at the right side of the ridge.

Finally, the benchmark is achieved. It’s been sprinkling lightly for the past hour.

The peak register is hidden near the benchmark. Signed in.

From the top, came back down retracing the path up.

Arrived at the truck right around sunset, by the time I made it to I-8 it was well after 1900.

No CBP or DEA observed. I’m sure that they were observing me, though %^)

Over a year ago I decided that I needed some good filters for ADS-B reception on mountaintops. Not that I had an immediate need, I didn’t have anything on a mountaintop, but I suppose I had a little extra cash and felt excited to be able to imagine a good ADS-B receive site atop an Arizona mountaintop (or hilltop) location. So, I drafted up what I thought would be a reasonable spec and went into Alibaba to find a filter manufacturer to build one. I ended up with 5 filters, all exactly to my spec, and for a bargain price (well, relatively speaking).

Above is the finished ADS-B receiver assembly, complete with Raspberry Pi, RTL-SDR 1ppm TCXO SDR dongle, a eBay-purchased LNA, an eBay-purchased 12 vdc to 5 vdc DC-DC converter, and some coaxial cabling (also from eBay). The black square in the center of the image is the 1090 MHz filter, and it’s a quite good one.

Solid out of band rejection, and I suspect around -100 dB ultimate rejection. The SA just doesn’t have the range to see it.

While the signal of interest is only a MHz wide, I wanted a filter that was wider so that temperature and mechanical variation would never haunt me, and I wanted a low bandpass loss (the above shows less than 1 dB loss) across the band.

Behind the filter is a run-of-the-mill eBay wideband LNA with a 1 dB NF, and somewhere around +30 dBm IP3. The RPi is running the most current version of FlightAware’s PiAware, rev 3.0.4, and supports just about any off-the-shelf USB SDR dongle.

After setting it up, it looked like I needed to reduce the overall gain a bit, so I discovered how to go into dump1090 and change the gain from “automatic” (really not, I think it’s just max) to 42 dB. That gave me best range and most received a/c.

Coverage seems to be pretty close to the model generated by HeyWhatsThat.com (above). The blue line is the 40,000′ contour, while the orange line is the FL300 contour.

24 hours or so of actual flight logs produces the following plot, which is more or less pretty similar to the HeyWhatsThat plot.

The primary notch in the pattern, in the SE, is the higher part of the ridge on which the radio site sits. It ends up blocking any coverage of flights in and out of Tucson, over 110 miles away, until said flights get to FL300 or so.

It will be interesting to see how the coverage shapes out over the next few weeks – I hope that it will get up near the top of all the local receive sites in performance.

Installed an ADS-B receiver up on White Tank Mountains over the weekend. Coverage seems pretty darned good, and I lose a/c only when they’ve gone about 1.5° below the theoretical horizon.

Below is a screenshot of the display. The a/c out beyond the 200 nm range ring are all at FL300 or greater, but at least according to heywhatsthat.com, they’re all significantly below the local horizon from White Tank.

Also seems that I have about a 10 dB dynamic range on the receiver. Signals are never stronger than about -1.6 dBFS and I always lose the a/c when the signal drops below about -12 dBFS. Using HeyWhatsThat.com, it’s very apparent when it drops out.

Here’s AAL110 headed NE from LA. I lost it as it was about due east from Cedar City UT.

The RSSI is below the minimum required for this particular station to decode successfully. Not that the a/c is over 220 nm distant, but it’s at FL410. So why did it suddenly fade out? HeyWhatsThat gives an indication.

From this plot, it’s obvious that the a/c, even at 41k feet altitude, is well below the local horizon and the actual path is probably ducting or multiple knife edges. Either way, it seems to explain for me why I can’t hear farther than this even with the receiver atop a significant “hill” in the Phoenix area.

Monitoring aircraft via ADS-B is a terrific hobby and super easy to do. I get to have a display here that shows sometimes hundreds of aircraft (both commercial and general aviation) out to about 200 miles from the house.

The above screen capture was from my Raspberry Pi running PiAware and connected to a homebrew 1090 MHz antenna up on the roof of the house. Nothing special in the setup, but look at the range! A/C at altitude are hearable out over the Grand Canyon and into California. Occasionally I get a/c into or out of Mexico, and I can see traffic in the southwest corner of New Mexico.

I’m planning to put one of these receivers on a local hilltop, about 3000′ above my house and the Valley floor, and yesterday installed the antenna on a temporary mount on the tower at the site. I connected it to my most recent ADS-B receiver setup, seen below, and was awestruck at the coverage. Was seeing a/c over Los Angeles and Albuquerque!

It’s a bit tricky to put a cheap SDR dongle anywhere near radio transmitters, and the hilltop that I was on is loaded with them. In fact, the building in which I have some current monitoring equipment is only 50′ away from a huge comms tower with dozens of two-way radio antennas, and a lot of potential interference. The ADS-B receiver antenna is right in the center of the picture, on the end of a piece of unistrut attached to the tower legs. In the background, nearly a dozen towers bristling with antennas.

The secret to success is a very good filter in front of the SDR receiver. That black square near the middle of the picture is exactly that. It’s a custom-made cavity filter, only 50 MHz wide, centered at 1090 MHz. Extremely sharp rolloff and ultimate rejection about 100 dB. Really helps the RTL-SDR receiver.

However, I wasn’t able to leave the receiver up on the hill yesterday, I was troubleshooting other issues and didn’t have time to set up the network connection to my receiver. Next time I will hopefully get it installed and on the air!